Question

1) Using the standard reduction potentials table in your book/notes, what is the standard change in gibbs free energy for the following reaction in kJ?

2NO₃^-(aq) + 8H⁺(aq) + 3Cu(s) → 3Cu²⁺(aq) + 2NO(g) + 4H₂O(l)

If you took CHEM 122 lab here, this was the first reaction in the cycle of copper lab that released the brown NO gas.

2) What is the value of K at 298K for the following reaction? (Please give your answer to two significant digits in scientific notation) K = e^nFE°/RT

3A²⁺(aq) + 2B(s)→ 2B³⁺(aq) + 3A(s)

A²⁺(aq) + 2e^- → A(s) E°_red = −0.58 V

B³⁺(aq) + 3e^- → B(s) E°_red = − 0.75 V

3) What is the cell potential for the spontaneous concentration cell with the reaction Fe³⁺(aq) + Fe(s) → Fe(s) + Fe³⁺(aq), with concentrations of Fe³⁺ of 0.848M and 0.353M at a temperature of 310. K?

E_cell = E°_cell −(RT/nF)lnQ

4) Which of the following will increase the cell potential for the following reaction:

2Fe³⁺(aq) + 3Zn(s) → 3Zn²⁺(aq) + 2Fe(s)

Use the reaction E_cell = E°_cell − (RT/nF)lnQ and consider how each manipulation affects Q and thus affects E_cell

_{- Add zinc solid}

_{- Remove water from the entire system}

- Add solid iron to the system

- Increase the concentration of zinc ion in solution

- Dilute the entire system

- Increase the concentration of Fe3+ in the solution